A sample of poisoned meat that killed a dog in northern Wisconsin.(Photo: Courtesy of the Wisconsin Department of Natural Resources)

State and federal wildlife agencies are investigating several cases where pet dogs and wild animals were fatally poisoned in at least three northern Wisconsin counties.

Since December, at least four dogs have died from eating poisoned meat in Bayfield, Marinette and Florence counties, according to the Wisconsin Department of Natural Resources. It's unknown if other counties could be involved. Investigators found dead coyotes, raccoons, weasels and one wolf they suspect were also poisoned.

The poison was found on the ground on public properties managed by the U.S. Forest Service and the Goodman Timber Co. Each dog died less than 30 minutes after ingesting the poisoned meat, according to the DNR.

Regional conservation warden David Zebro said one dog owner reported their pet was foaming at the mouth and had a seizure after eating the poison.

In all four cases where the dogs died, the poisoned meat was found in a road ditch, Zebro said. The DNR encourages dog owners to keep their pets on a leash when outside and keep them away from roadside ditches.

The DNR sent samples of the tainted meat to the Wisconsin State Crime Lab for testing. In addition to the DNR, the U.S. Forest Service and U.S. Fish and Wildlife Service are also investigating these deaths.

Anyone with information or a tip — no matter how insignificant it might seem —should contact the DNR violation hotline by calling or texting 1-800-847-9367 or reporting online at dnrx.wisconsin.gov/rav/. Tipsters can remain anonymous.